"I'd like to see some real data points regarding this alleged "XT problem" and not the "concern"-mongering, "Some say.."-ing, and internet folklore regurgitating that seems to accompany this topic whenever it's raised."

I wouldn't, what would the single data point of one user tell us that you wouldn't dismiss with the thought it was an outlier or just bad maintenance. Some of the reasons for Rohloff failure are from the same kind of cause. It wasn't actually designed for touring use, and quite transparently, on the basis a hundred or more years of touring bikes, the MTB strategies used to build the Rohloff lead to some weak point. I do think it is rational to go on track record (tells against companies that are constantly innovating) and on the basis of design. Experience alone will not always be the reliable guide. Also it is a different fault in logic to the one that you point out to assume that because a material is acceptable in one use, it will therefor work in others. Like aluminum ball bearings would not be a good idea just because the material works in handlebars.